Marin Alcatraz JR 24" 2025 Kids Jump Bike
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Details
We’ve taken the Alcatraz 1 and scaled it down for smaller riders. Built upon the same tubing as the larger models, it features a 360mm reach, 69° headtube angle, and 72° seattube angle, with 369mm chainstays.
A suspension-corrected rigid CrMo fork is designed to handle rough-and-rowdy riding, and a simple and stout single-speed drivetrain and Tektro mechanical disc brakes ensure a fun and safe ride.
Specification
Frame | Series 3 6061 Aluminum, 24” Wheels, 135×10mm Horizontal Single Speed Dropouts, 73mm Threaded BB, ISCG 05 Tabs |
Fork | Marin Series 2 CroMo 24”, Suspension Corrected, 100×9mm Dropouts |
Rims | Marin Custom Extrusion, 27mm Inner, Pinned Joint |
Rear Hub | Forged Alloy, 135×10mm, Bolt-On, Quad Sealed Bearings, Disc, 32H |
Front Hub | Forged Alloy, Bolt On 3/8” Axle, 100mm Spacing |
Spokes | 14g Black Stainless Steel |
Tyres | Vee Tire, Rail 24×2.25”, LSG Compound, Wire Bead |
Crankset | Marin Forged Alloy, Alloy 32T DM Chainring, 155mm Length |
Bottom Bracket | External Sealed Cartridge Bearings |
Chain | KMC HL-1 |
Rear Sprocket | 14T Single Speed Cog |
Front Brake | Tektro MD-M280 Mechanical Disc 160mm Rotor |
Rear Brake | Tektro MD-M280 Mechanical Disc 160mm Rotor |
Brake Levers | Tektro CL-330TS Alloy |
Handlebar | Marin Riser, 6061 Double Butted Aluminum, 31.8mm at center bulge, 38mm Rise, 700mm Width, 4º Up, 9º Back |
Stem | Marin 3D Forged Alloy, 31.8mm clamp, 35mm extension |
Grips | Marin MTN, Closed End |
Headset | FSA No 57E, Semi-Sealed Cartridge Bearings, 1 1/8” × 1 1/2” |
Seatpost | Marin Alloy, 30.9mm |
Saddle | Marin DJ Saddle |
Pedals | Alloy Platform |
Extras | Marin Chain Tension Device |
Specifications are subject to change without notice
Geometry

Frame Size | Short |
A – Stack | 525 |
B – Reach | 360 |
C – Headtube Angle | 69° |
D – Headtube Length | 112 |
E – Seattube Angle | 69° |
F – Seattube Length | 320 |
G – Toptube Effective | ? |
H – BB Height | ? |
I – BB Drop | 8mm |
J – Chainstay | 369 |
K – Wheelbase | ? |
L – Standover Height | ? |
M – Fork Offset | 42 |
Seatpost Diameter | 30.9 |
Handlebar Width | 700 |
Stem Length | 35 |
Crank Length | 152 |
Want to compare the size of your current bike to this one? Read our Reach and Stack guide here.
Manufacturer | Marin |
---|---|
RRP | No |